My "life story" is not to dissimilar. I tried for years to becomean RAF pilot but had very minor medical issues. In the end I joined up as a flight eng. But even this was not enough. I ended up paying my own way through an ATPL and was lucky enough to get a job after a short while. My advice is go for it. It will eat at you every day if you don't. Even Observer or WSO wouldn't be enough because you sit behind someone thinking I could do that. I know of 1 guy who tried several military career paths but has now thrown it all in to learn to fly. I didn't start it all until I was well in my 30's and although it's turned out alright I wish I had done it sooner. As for military/civvy aptitude it doesn't really matter. I know of guys who failed military and easily passed civvy. Mlitary aircrew courses are high pressure, 2 strikes and your out. In civvy world if you fail you just write out another cheque! Don't follow the promised military career if it's not what you really want. Good Luck
Boose Driver
PS Every military course I have ever been on is the hardest 1 ever !!